Reducing the cost of calculations for stability analysis of tall buildings using a new approach



This research proposes an innovative method to convert the modeling of three-dimensional structures to the modeling of two-dimensional structures for the stability analysis of long tubular buildings. The process of the proposed method is in the form of modeling the equivalent frame and then modeling the reduced frame using the equivalent moment of inertia for beams and columns. The second-order elastic analysis has been performed considering the effects of P-Δ and P-δ. Framed-tube and frame tube-in-tube systems have been used for modeling. Newton's Raphson and Crisfield's Arc Length methods have also been used for nonlinear analysis. The accuracy and speed of analysis of the new method have been checked by comparing the displacements and drifts in the modeled systems for 40 and 50 stories tall buildings. For each structure, two framed-tube and tube-in-tube systems are considered. In the presented method, the number of nodes and elements in the reduced model is much less. The method presented in this research can reduce the amount of calculating the response of tall structures and the duration of the analysis. One of the advantages of the presented method is the acceptable accuracy of the analysis along with the high speed of the analysis. The results show that the proposed method has reduced the amount of calculations by 80% along with a 5% reduction in the accuracy of structural responses.